The report was based on mobile advertising data captured from links and banners served to thousands of AdMob publishers. Even though the iPhone is not widely available in many international markets, AdMob's data shows that it still owns a sizable slice of the traffic -- about 33% of the traffic monitored by AdMob's network. The best-selling Nokia phones were responsible for about 22% of traffic, and RIM phones -- the BlackBerry 8100 and 8300 -- have 7.4%. The Palm Centro has 2.6% of the market, AdMob reported.

However, the report was limited by AdMob's network. While it serves ads in 160 countries and territories, some markets are over-represented, according to Nicole Leverich, a spokesperson for the company.

"Since this report is based solely on our data, it is biased in some respects," she told The Industry Standard. "[It] does reflect where AdMob's network of publishers is strongest."

In a country-by-country breakdown, AdMob found that about 44% of all its ad requests came from the United States. Coming in second was Indonesia, with about 14%. But other countries that are known to have large numbers of mobile users, such as China, did not register in the top 10 countries on AdMob's list for February.

The growing number of smartphone users worldwide is expected fuel the smartphone application market, according to a different report by In-Stat. According to the In-Stat report, iPhone users are "by far the most active apps store users."